let geyao= {
    name:'geyao',
    age:18,
}
let fangfang = {
    name:'fangfang',
    age:18,
}

let show = function(sex) {
  console.log(this.name+ "是" + this.age,'性别'+sex,'棒棒哒');
}


Function.prototype.myCall = function(context=window,...args) {
  const fn = Symbol('fn')
  context[fn] = this
  const result = context[fn](...args)
  delete context[fn]
  return result

}

show.myCall(geyao,'男')